1. Field of the Invention
The present invention is generally directed to an electronic navigational device employing a receiver for receiving GPS satellite signals. More particularly, the present invention is directed to an electronic navigation device and method for displaying cartographic markers in an abbreviated manner.
2. Description of the Related Art
Electronic navigation devices employing GPS receivers have become increasingly popular in recent years. The devices utilize an electronic navigation system which permits a user of the system to determine his or her position with respect to the earth. Such navigation devices are extremely useful in navigational vehicles of all types, including aircraft, marine craft, and land vehicles. Additionally, the devices are useful for tracking purposes, and hand held versions are popular with hikers and campers.
Very generally, conventional electronic navigation devices employ a receiver which detects signals from a number of satellites orbiting the earth. A processor within the navigation device computes the location of the device, based upon data received from the received satellite signals, after a sufficient number of GPS satellite signals have been acquired. Particularly, once a significant number of GPS satellite signals are acquired, the device is able to calculate its position with respect to the various satellites. Thus, an electronic navigation device employing a GPS receiver has the ability to accurately compute the position of the device in real time, even as the device moves. Additionally, the device is able to calculate the velocity and direction in which the device is moving in three dimensions.
U.S. Pat. No. 5,323,164 to Endo teaches a Satellite Radio Wave Capturing Method for Global Positioning System Receiver. U.S. Pat. No. 5,225,842 to Brown, et al. teaches a Vehicle Tracking System Employing Global Positioning Satellites. Each of these patents is incorporated herein by reference.
Both recreational and professional users of navigation equipment seek intuitive representations of navigation information which are direct and simple to interpret. The ability of a navigation device to present navigation information in a manner that is simple to interpret is particularly important for professional users, who use the equipment as one basis for navigating a vessel, such as an aircraft or marine craft.
Conventional navigational devices permit a user to input a number of waypoints, and thereby define one or more navigational routes. Additionally, the user can input waypoints to identify points of interest or hazards. In particular, conventional navigational devices have a large volume of cartographic data stored in memory. Using a keypad input, a user can input a waypoint corresponding to a geographical location. A waypoint is typically entered by placing a pointer at a desired location on the display screen displaying cartographic map data, and pressing an enter button to enter a waypoint at the selected location. In the past, navigational devices typically allocated a number to each waypoint entered into the device. Thus, for example, an initially entered waypoint would be allocated to No. 1, a subsequently entered waypoint would be allocated to No. 2, and soon.
In conventional GPS navigation devices, upon entering a waypoint, the user has the ability to define the waypoint with a character string. While a number of user interfaces are commonly employed, one popular approach is to permit a user to highlight the number associated with the entered waypoint, and press a button to retrieve a list of alphabetic characters. Then, using arrow or scroll keys, the user can select a desired alphabetic character for each of a defined number of locations, to thereby create a character string, for display on the display screen. The defined character string readily identifies the geographic location associated with the selected waypoint. For example, a navigator may select as a waypoint Olathe, Kans. As stated, this is accomplished by moving a pointer to the location of Olathe, Kans. on a map displayed on the display screen of the navigation device and pressing an Enter button. In the manner described, the user can then enter a character string to identify the selected waypoint as Olathe, Kans. However, it will often be necessary for the operator to abbreviate the name of the geographic location to allow it to fit within the defined number of spaces permitted for the character string.
As will be appreciated, while the ability to enter a character string which identifies a particular waypoint is desirable, the method in which this is carried out in conventional devices is extremely cumbersome and time consuming. In addition to the operator having to mentally determine an appropriate abbreviation in many instances, the operator must then physically enter that abbreviated character string into the memory of the device using the keypad. Thus, for example, for a character string that is to be six characters, the operator would have to individually select and enter each of the six characters, which requires a great deal of scrolling through characters and selecting the appropriate character for each space in the string. Thus, conventional devices require the operator to execute a great number of keystrokes or input functions just to enter and store a character string indicative Of a single waypoint. If multiple waypoints are desired, as is usually the case, this process becomes extremely time consuming and frustrating for the operator.
Accordingly, the need exists for a navigational device which permits an operator to easily identify a waypoint with a meaningful character string. More particularly, the need exists for a navigational device which relieves the operator from having to mentally configure an appropriate abbreviation for a geographic location, when necessary, and further relieves the operator from having to execute a substantial number of keystrokes or input functions in order to enter a character string indicative of a selected waypoint. The present invention overcomes the drawbacks of the prior art, and meets the foregoing and other needs.